Thermostatic alarm



Nov. 28, 1933.

Filed July 26, 1932 2 Sheets-Sheet 1 56 k /z* a Inventor m z iz'a/z w fl ltorne y 1933 F. H. PIETZSCH 3 0 THERMOS TAT I C ALARM Filed July 26, 1932 2 Sheets-Sheet 22 Inventor Patented Nov. 28, 1933 UNITED STATES OFFICE Application July 26, 1932. Serial No.' 624,8 24 i 4 Claims, (01. 116-103) This invention relates to an improved thermostatically controlled alarm.

An important object of my invention is to provide a simple, economical and dependable l thermostatically controlled audible alarm usable in a room or other enclosure to warn of abnormal heat conditions.

Another important object of my invention is to provide a device of the character described which is capable of being modified to act efficiently as a practical and eflicient fire alarm or as a temperature indicator for use in a sick room, or nursery.

In the accompanying drawings there .is shown a preferred embodiment of the invention;

Figure '1 is a front elevational view of the .embodiment of the invention.

Figure 2 is a side elevational view of Figure 1. Figure 3 is a vertical longitudinal sectional view t through Figure 1 disclosing interior mechanism.

Figure 4 is .a horizontal sectional view taken through the lower part of Figure 1 'andlooking downwardly.

Figure 5 is a vertical transverse sectional view through Figure 5 looking toward the left.

Referring to the drawings in detail, wherein like numerals refer to like parts through the same, the numeral 6 designates generally a supporting medium comprising the open-ended box portion tion 8 on the front face of which is secured the alarm mechanism housing 9.

The box portion 7 and the standard portion 8 are composed by sheet metal members 10, 11. The

'35' sheet metal member 10 comprises the Lshaped portion 12 having the right angular, short vertical flange 13. The sheet metal member 11 comprises the horizontal bottom portion 14 having at its front end the short vertical flange 15 bolted as indicated at 15 to the back of the vertical front portion of the member 10, and the vertical back portion 17 having the short horizontal portion 18 which has the tall vertical plate 19, to the front 5 a supporting medium 22.

24 to the front face of the plate 19 by means of bolts 25. Surrounding the front of the housing 23 and spaced therefrom is theishell 26 constituting an alarm bell. It is attached by screws 27 to 7 from the top of which rises the standard portive.

A cylindrical housing 23 is secured by its flange structure of the'ihousing 23 and haslan opening "28in its front wall.

,Within the box portion 'Tisfa muniine wafer .type thermostat unit29 which is mounted on the bottom 14 hy a bolt or binding post which passes fiO therethrough and has a nut 31 thereon operable for clamping .an "electrical conductor between it and the'bottom 1114'. A Washer 32 separates the thermostat" unit efromth'e bottom .14; on the top element of the thermostat. unit 9 is a contact head 33in circuit with thefbinding pdstBD. The

box portion'y'l acts as a shelter for the thermostat against vagrant currents of air, which might be alternately cool and hotf-and functions to confine about thethermostat the heated air which enters the open ends of the box portion and which is in point of temperature, representative of the temperature of the air in the place in which the device is located; sothat the thermostat-is conditioned to operate on a mean levelofhightemperature in the place in which is'locatedfi The alarm mechanism comprises the spring motor driven gear wheel 34 which -is suitably mounted on shaft -*35withir'i'-'the housing 23. The wheel 34 is in ;me'sh with a small-pinion 36 fixed for rotating an -escapeme nt wheel37, Rockably mounted at 3B is the inverted J shaped bell hammer operating member 39 which has within its crook the spaced dogs 40 for cooperating with the teethof the'esc'apement 35 wheel 37. Pivotally connected 'tothe lower end of the member 39 as indicated at 41 is one end of the link 42 whoseother end is pivotallyjconnected as indicated at '43 'to an intermediate portion of the bell hammer 44. The bell hammer 44 is "'pivotally mounted at its lower endas in'di-' ca-te'dat 45 and has on its upper end theha'rrmier head 46 which operates through an opening 47 in the side of the housing 23 for strikingthe-bell 26.

Pivotally mounted as indicated'at'48 is an L- shaped latch member 49 whose upper end is formed to hook over a portion of the member 39 indicated by the numeral 50, to hold the member 39 in a position in which the bell hammer-44is withdrawn from the opening 47 and held inopera- Means forreleasing the latch 49-f-rorn the member 39 so as to permit the member 39 to be moved by the esapement wheel' 40 for operating ing 23 and presses upon the upper side of 9, lug 54 on the latch for holding the'latch normally engaged with the member 39 in the manner shown in Figure 3. The rod 51 passes through the wall of thehousing 23 and through the top of the box portion 7 in axial alignment with the contact head 33 of the thermostat unit. An opening 55 in the top of the box portion is of sufiicient size to enable a head 5'? on the lower end of the rod to move freely therethrough when pushed upwardly by the expansion of the thermostat unit. Between the head 5'7 and the wall of the housing 23, there is circumposed upon the rod 51 a return spring which normally forces the rod 51 downwardly and assists the leaf spring 53 in holding the escapement mechanism inoperative. The head 57 is in the nature of a binding post for connecting a conductor, and carries adjustable contact point 58, to be electrically engaged by contact head 33 of the thermostat, when the thermostat expands, for closing an electrical 1 alarm circuit (not shown) When the thermostat expands upwardly and engages the contact point 58 and pushes the rod 51 upwardly, the alarm circuit is closed and the latch 49 rocked on its pivot 48 in a direction to disengage it from the member 39, whereby the member 39 is freed to be rocked to and fro by the escapement wheel 3'1 and ring the bell 26 with the hammer 44. When'the thermostat contracts again, the spring 56 will push the rod 51 downwardly into its initial position assisted by the .leaf spring 53. This action re-engages the latch with the member 39 and resets the alarm.

It is evident that the structure is electromechanical in nature in that it permits the actua- -tion of anelectrical alarm at a remote place si- .mu1taneously with the operation of the local mechanical alarm.

As before stated, the invention may be used as a fire alarm or may be used as an ordinary room temperature alarm in connection with heating systems indicating excessive heat.

Particular attention is called to the specific construction of the sheet metal support which is designed to support the elements of the device of the invention in proper operative relationship to insure durability and efiiciency in operation.

It is thought that the description taken in connection with the drawings enables a clear understanding of the invention. Therefore, additional description is thought to be unnecessary.

While the preferred embodiment of the invention has been shown and described, it is to be understood that minor changes coming with- 1 in thefleld of invention claimed may be resorted to if desired.

I claim: i I 1.-In a'structure of the class described, a supporting fixture made up of a pair of companion sections, each section being of sheet metal, one

section being bent to form the major portion of an open-ended rectangular housing and a supporting panel, the remaining section being formed with flanges attached to the panel and said first-named section to complete the housing, brackets for mounting the housing on a supporting thermostat carried by the said support for stat when the thermostat expands.

2. In a structure of the class described, a supportingfixture made up of a pair of companion sections, each section being of sheet metal, one section being bent to form the major portion of an open-ended rectangular housing and a supporting panel, theremaining section being formed with flanges attached to the panel and said firstnamed section to complete the housing, brackets for mounting the housing on a supporting medium connected to said first-named section, an expanding thermostat mounted in said housing, an audible mechancally operated alarm supportedon said panel and including releasing means, push rod means extending from the releasing means through an opening in the housing into the interior thereof and arranged to be engaged and operated by said thermostat when the thermostat expands, said thermostat being formed with a contact and a binding post, and said pushrod being formed with a complemental binding post and contact engageable' for closing a circuit when I05 I casing, an operative connection between the push rod and trip latch, and an expanding thermostat carried by said support for operatively engaging the push rod when the thermostat expands.

4. In an alarm structure of the class described, a support including mounting means, a thermostat carried by the support, an alarm carried thereby, said alarm including a casing having its wall formed with an opening, a bell surrounding the casing, a hammer pivotally mounted in the casing and operable through the opening to strike the bell, a clockworks supported in said casing. for operating the hammer, a trip latch for releasing the clockworks into operation, a spring returned push rod operable through an opening provided in the casing; an operating connection between the push rod and trip latch, an expandoperatively engaging and'pushing the push rod when the thermostate expands, an electrical contact on the push rod, a second electrical contact on the thermostat for engaging the first contact when the thermostat expands to close an alarm "40 circuit in which the contacts are interpolated.

' FRANK H. PIETZSCH; 

